bygmyke -
In addition to the suggestions provided by postino and Marc I can only share that I have had a similar experience. It might be a weak striker spring.
One of my Lugers would not fire. It would just "click" and the indentation in the primer was barely visible. Upon taking it apart, I discovered the striker spring was too short. (I think someone had cut a few coils out of it.) I put in a new one, and the pistol functioned flawlessly.
You can probably get a new striker spring from Luger Doc on this Forum.
Or you can order a service pack which includes the striker spring here:
http://www.gunsprings.com/index.cfm?...s&cID=1&mID=38